Learn about the similarities and differences of NASH and NAFLD.
What are NASH and NAFLD?
Non-alcoholic fatty liver disease (NAFLD) includes two types of conditions: non-alcoholic fatty liver (NAFL) and non-alcoholic steatohepatitis (NASH). Both NAFL and NASH are classified as diseases of the liver but are distinct from each other. NAFL, also known as fatty liver, is a disease in which fat builds within the cells of the liver (steatosis) in the absence of any significant inflammation or fibrosis (scarring). NASH, like NAFL, has steatosis, but is associated with significant inflammation and scarring.
It is important to note that these conditions are diagnosed only in the absence of other causes of steatosis, most importantly alcohol-related liver disease(1).
What are the similarities between NASH vs. NAFLD?
NAFL and NASH are similar in that both result from fat building up in the liver cells, predominantly in people with risk factors that include:
- Type 2 diabetes
- Metabolic syndrome (a combination of a large waistline, high blood pressure, low HDL cholesterol, high triglycerides, and diabetes)
Both normally do not cause any symptoms and both may be incidentally discovered either through routine blood work or from an imaging study. It is also important to note that patients with NAFL and NASH are at increased risk for heart disease(1).
What are the differences between NASH vs. NAFLD?
Percent of the population with the condition
Risk factors for NAFLD include obesity, diabetes, high blood pressure, and other components of the metabolic syndrome. In the United States, approximately 30% of the population may have some form of NAFLD, with some studies reporting rates as high as 46%(1,2). Global estimates suggest approximately one in four people may be affected(3). NAFLD may be more common in certain ethnicities, such as the Hispanic population, due in part to higher rates of obesity and a genetic predisposition(4). Because the disease is largely one without symptoms, we may not know the exact number of people affected. Approximately 10–20% of people with NAFLD will be diagnosed with NASH(5).
What treatment options are available for NASH?
Currently, there are no approved medical treatments to reverse the liver damage caused by NASH. However, there are clinical research studies that may lead to future treatments, including a NASH research study available through Science 37. If you or a loved one has a NASH diagnosis, see if you qualify for this opportunity. Compensation may be provided.
- Williams CD, Stenger J, Asike MI, Torres DM, Shaw J, Contreras M, Landt CL, Harrison SA. Prevalence of nonalcoholic fatty liver disease and nonalcoholic steatohepatitis among a largely middle-aged population utilizing ultrasound and liver biopsy: a prospective study. Gastroenterology 2011;140(1):124-131.
- Browning JD, Szczepaniak LS, Dobbins R, Nuremberg P, Horton JD, Cohen JC, Grundy SM, Hobbs HH. Prevalence of hepatic steatosis in an urban population in the United States: impact of ethnicity. Hepatology 2004;40(6):1387-1395.
- Younossi ZM, Koenig AB, Abdelatif D, Fazel Y, Henry L, Wymer M. Global epidemiology of nonalcoholic fatty liver disease—Meta-analytic assessment of prevalence, incidence, and outcomes. Hepatology 2016;64(1):73-84.
- Romeo S, Kozlitina J, Xing C, Pertsemlidis A, Cox D,Pennacchio LA, et al. Genetic variation in PNPLA3 confers susceptibility to nonalcoholic fatty liver disease. Nature Genetics 2008;40(1):1461-1465.
- Younossi ZM, Blissett D, Blissett R, Henry L, Stepanova M, Younossi Y, Racila A, Hung S, Beckerman R. The Economic and Clinical Burden of Nonalcoholic Fatty Liver Disease in the United States and Europe. Hepatology 2016;64(5):1577-1586.